Afraz Ahmadreza, Rafati Amir Abbas, Najafi Mojgan
Department of Physical Chemistry, Faculty of Chemistry, Bu-Ali Sina University, P.O. Box 65174, Hamedan, Iran.
Department of Physical Chemistry, Faculty of Chemistry, Bu-Ali Sina University, P.O. Box 65174, Hamedan, Iran.
Mater Sci Eng C Mater Biol Appl. 2014 Nov;44:58-68. doi: 10.1016/j.msec.2014.07.065. Epub 2014 Aug 2.
We describe the modification of a carbon paste electrode (CPE) with multiwalled carbon nanotubes (MWCNTs) and an ionic liquid (IL). Electrochemical studies by using a D-optimal mixture design in Design-Expert software revealed an optimized composition of 60% graphite, 14.2% paraffin, 10.8% MWCNT and 15% IL. The optimal modified CPE shows good electrochemical properties that are well matched with model prediction parameters. In the next step, the optimized CPE was modified with gold nanostructures by applying a double-pulse electrochemical technique. The resulting electrode was characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and electrochemical impedance spectroscopy. It gives three sharp and well-separated oxidation peaks for ascorbic acid (AA), dopamine (DA), and uric acid (UA). The sensor enables simultaneous determination of AA, DA and UA with linear responses from 0.3 to 285, 0.08 to 200, and 0.1 to 450 μM, respectively, and with 120, 30 and 30 nM detection limits (at an S/N of 3). The method was successfully applied to the determination of AA, DA, and UA in spiked samples of human serum and urine.
我们描述了一种用多壁碳纳米管（MWCNTs）和离子液体（IL）修饰碳糊电极（CPE）的方法。使用Design-Expert软件中的D-最优混合设计进行的电化学研究表明，优化后的组成为60%石墨、14.2%石蜡、10.8% MWCNT和15% IL。优化后的修饰碳糊电极表现出良好的电化学性能，与模型预测参数匹配良好。下一步，通过应用双脉冲电化学技术，用金纳米结构对优化后的碳糊电极进行修饰。所得电极通过扫描电子显微镜、能量色散X射线光谱、X射线衍射和电化学阻抗谱进行表征。它为抗坏血酸（AA）、多巴胺（DA）和尿酸（UA）给出了三个尖锐且分离良好的氧化峰。该传感器能够同时测定AA、DA和UA，线性响应范围分别为0.3至285、0.08至200和0.1至450 μM，检测限分别为120、30和30 nM（信噪比为3）。该方法成功应用于加标人血清和尿液样本中AA、DA和UA的测定。
